Transparent silicon/glass microreactor for high-pressure and high-temperature reactions

To increase mass transfer in solid catalyzed gas–liquid hydrogenations, the reactions are often operated at high pressures. Silicon/glass microreactors present a possibility to safely handle high-pressure and provide optical access into the reaction channel for flow investigations. In this study we present a Si/glass microreactor with soldered microfluidic connections for high-pressure and high-temperature applications. Mechanical testing of the device by tensile and pressure tests showed no failure for continuous operation at 140 bar and 80 °C. The improved microreactor design is applied for a well-described solid catalyzed exothermic hydrogenation at operating conditions up to 51 bar and 71 °C. Additionally the two-phase gas–liquid flow is investigated in the microreactor. Results clearly indicated the improvement of the reaction rate from 0.004 mol gcat−1 min−1 at ambient conditions to 0.046 mol gcat−1 min−1 at 51 bar and 71 °C. The reaction was observed to be mass transfer limited.